Charging Effect by Fluorine-Treatment and Recess Gate for Enhancement-Mode on AlGaN/GaN High Electron Mobility Transistors

• Published in: Nanomaterials (Basel, Switzerland) Vol. 10; no. 11; p. 2116
• Main Authors: Kang, Soo Cheol, Jung, Hyun-Wook, Chang, Sung-Jae, Kim, Seung Mo, Lee, Sang Kyung, Lee, Byoung Hun, Kim, Haecheon, Noh, Youn-Sub, Lee, Sang-Heung, Kim, Seong-Il, Ahn, Ho-Kyun, Lim, Jong-Won
• Format: Journal Article
• Language: English
• Published: MDPI 24.10.2020; MDPI AG
• Subjects: AlGaN/GaN HEMTs; enhancement-mode; fluorinated-gate; recessed gate
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano10112116

An enhancement-mode AlGaN/GaN metal-insulator-semiconductor high-electron- mobility-transistor was fabricated using a recess gate and CF4 plasma treatment to investigate its reliable applicability to high-power devices and circuits. The fluorinated-gate device showed hysteresis during the DC current-voltage measurement, and the polarity and magnitude of hysteresis depend on the drain voltage. The hysteresis phenomenon is due to the electron trapping at the Al2O3/AlGaN interface and charging times longer than milliseconds were obtained by pulse I-V measurement. In addition, the subthreshold slope of the fluorinated-gate device was increased after the positive gate bias stress because of the two-dimensional electron gas reduction by ionized fluorine. Our systematic observation revealed that the effect of fluorine ions should be considered for the design of AlGaN/GaN power circuits.